net_sched: make cls_ops->change and cls_ops->delete optional

Some schedulers don't support creating, changing or deleting classes.
Make the respective callbacks optionally and consistently return
-EOPNOTSUPP for unsupported operations, instead of currently either
-EOPNOTSUPP, -ENOSYS or no error.

In case of sch_prio and sch_multiq, the removed operations additionally
checked for an invalid class. This is not necessary since the class
argument can only orginate from ->get() or in case of ->change is 0
for creation of new classes, in which case ->change() incorrectly
returned -ENOENT.

As a side-effect, this patch fixes a possible (root-only) NULL pointer
function call in sch_ingress, which didn't implement a so far mandatory
->delete() operation.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 0 insertions, 22 deletions

diff --git a/net/sched/sch_multiq.c b/net/sched/sch_multiq.c
index 912731203047..a0ffe7158ff3 100644
--- a/net/sched/sch_multiq.c
+++ b/net/sched/sch_multiq.c
@@ -348,26 +348,6 @@ static void multiq_put(struct Qdisc *q, unsigned long cl)
         return;
 }
 
-static int multiq_change(struct Qdisc *sch, u32 handle, u32 parent,
-                         struct nlattr **tca, unsigned long *arg)
-{
-        unsigned long cl = *arg;
-        struct multiq_sched_data *q = qdisc_priv(sch);
-
-        if (cl - 1 > q->bands)
-                return -ENOENT;
-        return 0;
-}
-
-static int multiq_delete(struct Qdisc *sch, unsigned long cl)
-{
-        struct multiq_sched_data *q = qdisc_priv(sch);
-        if (cl - 1 > q->bands)
-                return -ENOENT;
-        return 0;
-}
-
-
 static int multiq_dump_class(struct Qdisc *sch, unsigned long cl,
                              struct sk_buff *skb, struct tcmsg *tcm)
 {
@@ -430,8 +410,6 @@ static const struct Qdisc_class_ops multiq_class_ops = {
         .leaf           =       multiq_leaf,
         .get            =       multiq_get,
         .put            =       multiq_put,
-        .change         =       multiq_change,
-        .delete         =       multiq_delete,
         .walk           =       multiq_walk,
         .tcf_chain      =       multiq_find_tcf,
         .bind_tcf       =       multiq_bind,